1. Field of the Invention
The present invention relates broadly to the manufacture of float glass and, more particularly, to improved means for mounting linear induction motors which extend through the side walls of float glass apparatus.
2. Description of the Prior Art
As is well known, manufacture of flat glass by the float process involves delivering molten glass at a controlled rate onto a bath of molten metal which has a greater density than that of glass (such as tin or alloys of tin, for example) and advancing it along the surface of the bath under physical and thermal conditions which assure that a layer of molten glass will be established on the bath, that from the layer there will develop a buoyant body of molten glass of stable thickness, and that the buoyant body in ribbon form will be continuously advanced along the bath and sufficiently cooled as it advances to permit it to be taken from the bath by mechanical conveying means.
Above the bath of molten metal, an enclosed head space or plenum chamber is provided to contain the so-called float atmosphere. This atmosphere is generally a non-oxidizing gas (usually a mixture of gases such as nitrogen and hydrogen) maintained under sufficient pressure to prevent contamination by leakage of external atmosphere into the head space.
Various regulating or controlling devices such as coolers, heaters, water fences, edge rolls, top assistors and linear induction motors are inserted through the side walls of the bath structure to control conditions as the ribbon moves down the bath to assure that a ribbon having the proper characteristics is produced. These devices are generally supported on the floor or lower bath structure and connected to various utility service lines outside the bath structure, so that the area alongside the bath structure often becomes quite congested.
One proposal for alleviating some of this congestion is set forth in U.S. Pat. No. 3,929,444 to May et al which discloses a mounting device for an edge-roll machine adapted to engage and apply forces to the margins of a glass ribbon during its formative stage. The edge-roll machine is suspended beneath a carriage which rides on overhead rails extending longitudinally along the glass forming chamber. Provision is made for the barrel of the machine to be raised slightly so that the edge-roll is disengaged from the glass, and the entire carriage can then be moved horizontally along the rails to an out-of-the-way location so as to provide free access to the forming chamber at the edge-roll machine station.
Since considerable time is required to move or remove the regulating devices, they tend to hinder operating personnel when it becomes necessary to work on the bath under emergency conditions. This is particularly true in the case of linear induction motors mounted at the exit end of the bath structure for assisting in the collection and removal of dross from the bath of molten metal as disclosed in U.S. Pat. No. 3,467,512 to D. G. Loukes et al. The continuous glass ribbon for one reason or another occasionally breaks at the exit end where it is being removed from the metal bath. At such times it is necessary for operating personnel to quickly open up the sides of the bath structure, reestablish the ribbon and start it again moving through and out of the exit end of the bath structure. Heretofore, linear motors located in this area were a hindrance at such time and they either had to be removed, resulting in the loss of precious time, or the operating personnel had to work around them.